The stream rises from several sources in Chislehurst in the London Borough of Bromley and post code BR7 it then flows northeast under the A20 road Sidcup By-Pass into the London Borough of Bexley and DA15 passing through Longlands, Lamorbey and into Blackfen where it joins the longer River Shuttle in Holly Oak Wood Park. As Longlands, Lamorbey and Blackfen all have the post town Sidcup, Wyncham Stream could be said to flow through the outskirts of Sidcup.

Sidcup is a suburban development in the London Borough of Bexley, South East London. Located 11.3 miles (18.2 km) south east of Charing Cross, Sidcup is bordered by both the London Borough of Bromley and Kent County Council and whilst now part of Greater London, was once referred to as the gateway to Kent.

North End is an electoral ward in the London Borough of Bexley which consists of Slade Green, the eastern part of Erith and a tiny part of Barnehurst, along with parts of Northend. Community interests are represented by Slade Green Community Forum, which is a registered charity. There are approximately 4800 residences within the ward.